The present invention relates to a dispenser for a roll of web material, and particularly to a sanitary dispenser that dispenses a measured amount of material upon a user grasping and pulling the “tail” end of the roll material.
A number of dispensing devices are well known in the art for dispensing and cutting webs or roll material such as paper toweling. With such dispensers, the process of dispensing and cutting the web material is carried out automatically by a user pulling on the free “tail” end of the web material that extends from a dispensing slot in the apparatus. In a typical configuration, the web material is engaged against a rough friction enhancing surface of a feed drum and the action of pulling the web tail causes the drum to rotate. The drum includes a drive mechanism and, after the initial pull on the web tail by a user, the drum is driven a predetermined rotational degree to dispense a metered amount of the material. A cam driven cutting mechanism may be provided in the rotating drum that pivots out of a slot in the drum to automatically cut the web at the proper length. The dispensers typically include a stored energy mechanism, such as an eccentric cam, that is spring loaded during the initial rotation of the feed drum. This device causes the drum to continue to rotate after the web has been cut. This action causes an additional length of the web material to be feed out of the dispensing slot as the tail for the next dispensing sequence. These types of dispensers are commonly referred to as “no-touch” or “sanitary” dispensers because the user does not manually operate any portion of the drive or cutting mechanism. The user only touches the tail end of the web material.
Although effective, the conventional mechanical sanitary dispensers utilizing automatic mechanical cutting and feeding mechanisms can be relatively complicated from a mechanical component standpoint and expensive to manufacture and maintain. Also, some users have noted that such dispensers present an inordinate amount of resistance to pulling a towel from the dispenser. This may be particularly true when the initial pulling action by the user also provides the force needed to load the potential energy spring of the automatic tail feeding mechanism. Thus, web materials with relatively high tensile strength must be used with such dispensers.
Advances have been made in the art relating to purely electronic sanitary towel dispensers. With such dispensers, the unit is typically activated upon detection of motion of a user's arm or hand. A motor is subsequently energized through a control circuit and power source to drive a feed roll and thus dispense a measured length of material. The user then grabs the exposed material and pulls it at some angle to the dispenser cover causing the sheet of material to separate on a cutting edge or serrated tear bar. The cycle is repeated for the next user.
U.S. Pat. No. 3,730,409 discloses an electronic dispenser wherein initially a full measured length of towel hangs out of the dispenser. A user grabs and separates the towel by pulling it against a tear bar. A force activated switch is configured with the tear bar that activates a dispenser motor through a power source and electronic circuit upon the user tearing the towel. The motor then drives a feed roll to deliver a full measured length of towel material outside of the dispenser cabinet where it hangs for the next user to grab and tear. WO 00/63100 describes an electronic dispenser with a similar operating principle.
A significant drawback with conventional electronic dispensers is that electrical power is consumed by the motor to drive the full length of towel material from the dispenser. This greatly reduces the battery life of such systems resulting in frequent battery replacement and maintenance.
The present invention relates to a hybrid mechanical/electrical sanitary dispenser that addresses at least some of the drawbacks of conventional mechanical and electrical dispensers.